A half-duplex type transceiver transmits and receives on the same radio channel and is not able to receive while its own transmitter is in operation. This property of the half-duplex mobile radio may result in a situation in which the transmitter of the mobile radio is in operation when the call terminates during a call disconnect signal transmitted from the mobile exchange, and does not receive the disconnect signal but remains on the traffic channel even though the mobile exchange has cleared the call and released the traffic channel. The same channel can be allocated to a new call immediately after the release, and so the mobile radio remaining on the traffic channel after a preceding call may undesirably participate in the new call or at least hear the beginning of the call.
Previously, attempts have been made to solve this problem by transmitting special selective disconnect messages on the traffic channel in the beginning of the call, which messages command the mobile radios not associated with the current call to leave the channel. If the transmitter of the mobile radio remaining on the channel after the preceding call is still or again in operation even when such disconnect messages are being transmitted, the mobile radio does not receive the messages and will not leave the channel. Such disconnect messages can be transmitted continuously during the call, in which case they, however, deteriorate the call quality, causing short breaks.